Clayton Bay 144LV - 12ft plywood kayak

Have been evolving my stitch & glue CB144 design over the last few years in Gregg
Carlsson's "Hulls" proggy.
#1 had a delightful hull but terrible deck - as an ex-slalom boat paddler, I forgot to add
knee-room for big people like me. My wife & kids liked it though. (img-131m.jpg)

#2 got the knee room, but trying to be clever & add boatspeed, lost the stability
& handling of the original hull. #2 isn't a bad boat - just less forgiving. And its bigger
volume is off-putting to smaller people (like my wife & kids). (other 2 .jpgs)

Was going to build MIK's RAID41 this year, or Eureka, but SWMBO has been stewing
since April that I let #1 go to my sister interstate. So... all other projects on hold while
#3 takes shape.

#3 marries the good deck to the docile hull in a low volume version of the boat,
intended for paddlers 40-80kg with up to size 10 feet. Previous boats have been built
in 4mm pac.maple BS1088 & coated with 6oz glass. Weight around 12KG for #1 &
11KG for #2 - used peel-ply to good effect. Aiming to keep this one under 10KG using
2oz glass sheath instead of 6oz.

Ply marked out, panels aligned & joined using taped butts, started cutting out today.

Is it worth blogging it here? or has S&G kayaks been done to death already ?
cheers
AJ

AJ,
Put it up here. If people don't want to read it , they don't have to. I'm interested. I've just started building a Eureka with a few minor modifications. I scarfed my panels rather than the butt strap, so I'm interested in the taped butt join. Does it still bend ok, and are both sides taped?
Cheers,
Chris

G'day Chris

yes, it is taped both sides.
yes, it slightly alters the panel flex at that point, but as the panels have soft curves in
them, the stiff spot is almost undetectable. Far easier join to get 'right' than a scarf
for plywood joins like this. I prefer to scarf solid timber though.

pictures below

Some people do both sides of their taped butts at once, and even stack multiple sheets
to do them all in one go. While doing so eliminates the risk of the untaped (weak)
side of a single-side join cracking open during turning the sheet over, I found it a bit
more demanding than I am prepared to do regularly. With a bit of care, I have never
had a joint crack open in the 4mm that I use. Might be a different story trying to turn
an unwieldy double sheet of 25mm.
cheers
AJ

Like a lot of people, I have limited sized blocks of time available, so I tend to pick away
at odd bits & pieces, avoiding longer & tediouser jobs. Like marking or cutting out.

First boat I did without a strong-back - just used the ply bulkheads & panel shapes to form
the boat. It mostly worked, but I finished up with a slightly twisted boat - my ply was warped
& there was nothing solid to push/pull it into line against. I now use a strong-back with
formers at 3 fixed points. Costs a bit of time setting up, but once set up, many other parts
of the job become quicker & easier. Swings & roundabouts.

Getting the corners on the formers accurately located has always been something of a
trial. This time trying pushing a 2.5mm drill through each marked corner before
cutting & shaping. Seems to work well.

Marking out panels, I use a large metal square - 400mm x 600mm.
To provide references, I first mark the sheet into 500mm squares, starting from the
reference corner. Mark these lines in a fine pen, being extra careful to get them right.
Their accuracy is crucial to the rest of the measurement of the boat.

These 500mm spaced lines are the references for plotting up to 24 'X & Y' coordinates
for each of the 16 panels & bulkheads which will go into the boat.
Have I used the word "tedious" yet? If not, let me use it now !!
Also get cross-eyed from so many numbers, & simple errors creep in, like measuring
1107 instead of 1117. Important to step back & do sanity checks frequently - are the
X coordinates about the same distance apart ? Is the mark-out more-or-less
symmetrical across the sheet.

Then it's just a matter of joining the dots using a flexible batten for the curvy bits & a
straight-edge for the un-curvy bits. House bricks are functional "ducks" to hold the
batten in place. I use a different coloured pen to distinguish chine lines from the
original 500mm squares. Very easy to track onto the wrong line withe jigsaw
otherwise. Another great opportunity for additional sanity checks - unfair curves & etc.

Then cut the middle panel in half, & align sheets 1 & 3 to their respective half of sheet 2
to get the lines fair across the joins. Once the lines are complete, join the sheets with
panels correctly aligned. Tried to join individual panels on my first boat, but found
it almost impossible to get them perfectly aligned without marking their shape onto
my work table - a heap of extra work I can well do without!!

I like taped butts. Neat & easy to do. See earlier post on these.

AJ,
Ilike the way you think. Good idea joining the sheets before cutting them out. Personally, I probably would have set everything out so that the joins were staggered. But I haven't seen the plans, so I don't know if this is possible.
Thankfully for me, the Eureka is set out on the plans with square ends, so the cutting out and lining up when scarfing is very little trouble at all. (Thanks Mik). Just need to remember to allow the extra length for the scarf.
I'll probably post some photo's when the project is complete. There's been plenty of Eureka builds, so I'll just post the alterations I'm doing.
Cheers,
Chris

G'day Chris
The key difference between Eureka & CB is the width of the panels.
I don't have my Eureka plans in front of me, but I think the narrowest panel is about
180mm at the join. Plenty of width to force the join square. CB has a number of
panel joins which are about 40mm wide. Almost impossible to correctly align
individual joins without some sort of external template/mark-up.
cheers
AJ

Note to self.
Buy pack of 2 fine cut jigsaw blades before starting.
3.6M of cut each side of 10 panels, plus 3 or 4 permanent bulkheads plus the 3 x 19mm
chip-board formers = .... about 90M of cutting.

Second note to self.
If jigsaw becomes hard to push through 4mm ply, sometimes it's because the work bench
top is thicker than 4mm. But more often, it's because one foot is on the power cord...
:doh:

Third note to self.
Epoxy makes some inks turn invisible. Invisibility makes a line hard to follow with jigsaw.
Test ink on scrap of ply before committing several hours to its use. Or use dark pencil.

Quote:

---

Originally Posted by b.o.a.t.

If jigsaw becomes hard to push through 4mm ply, sometimes it's because the work bench
top is thicker than 4mm. But more often, it's because one foot is on the power cord...

---

My first build project was a stich and glue pram, the D5 by Bateau. Halfway through I decided it would be the sail version with centerboard. I drilled two holes at either end of the slot - just inside the bulkheads for the middle seat, rolled the boat over, inserted the jigsaw and began cutting.

Gee wiz! I thought. Cutting through fibreglass fillets is hard going. Suddenly the going became much easier as the blade finally made it through the bulkhead. I was cutting in the wrong direction!!!! :doh:

Quote:

---

Originally Posted by Darce

Suddenly the going became much easier as the blade finally made it through the bulkhead. I was cutting in the wrong direction!!!! :doh:

---

So far, touch wood, I haven't done that!!

All parts cut out now.
Making the chine panels identical with plane, spokeshave & sandpaper.
Finding differences in shape & size between chine pairs. Again.
Spent a few hours with an adding machine, checking numbers for sanity.
Unfortunately, they are all sane. That means the differences are id10t errors. :(

Worked out the biggest ones are where I reversed the direction of my square.
Conclusion... parallax errors lining the square up with the grid lines during mark-out.
I do my marking out on my work bench, not the floor, so I can't get my head vertically
above the middle lines of the grid. Could be avoided by doing mark-up on the floor :C,
or marking one side only, cutting & finishing it, then tracing item to other side of the
sheet. Then cutting & finishing that... I suppose the extra labour of two lots of finishing
would be largely off-set by reduced labour marking out parts.

Anyway... did the cockpit cut-outs today. The little triangular cuts are to allow the rear
of the cockpit to be a bit lower to easy ingress/egress. Will tape the cut-outs back in
place once the deck is assembled & shaped. Also have to hang onto the cockpit cut-
outs to use as a template for the coaming.

Can't believe it is really only a week since last touching it.
Alas, life & the need to earn a quid intrudes.

Could have chosen a nicer few days to have off-shift. 44C (111F) yesterday.
45C (113F) today. Cool change tomorrow - 41C. Maybe.
Predicted wind hasn't eventuated. Yet. No fires. Yet. Turn-out clobber set up
behind car so as to just step into boots, pull up pants & go. Water pouring out of skin
faster than can be poured down gullet. :C

Hopped into it yesterday anyway. Doing everything s-l-o-w-l-y to avoid sweating or
otherwise accellerating fluid loss.

Got the formers onto the strongback. It seems to have warped since last use. So
had to work out corrections for warp factor before starting. Got there in the end.
Formers aligned & affixed in 3D. THEN realised I'd put them on the right way up
instead of upside down. Heat must be addling brain. *shrug* Situation normal, I
suppose... Do the deck first rather than start former alignment all over...

A bit of tape on the corners of the formers prevents them becoming a part of the boat
when epoxy drips through the joins.

Drilled wire tie holes with deck panels clamped togther, threaded & very lightly twisted
wires - just enough to stop them falling out. Any tighter & they stop the panels
opening out flat. I use 0.9mm telephone jumper (hook-up) wire. The PVC sheath
allows it to be easily pulled out once the panels are edge glued.

Align deck panels fore-and-aft and side-to-side, & tack them in position on the formers.

Adding chine 4... a nail in the former just below the bottom edge holds it in place for
drilling & tying. Extra ties needed to hold it all together neatly through the complex
re-curve around the cockpit. Start from the middle & work out to the ends, drilling &
tying. Aiming for a completely even gap without wobbles & etc. Wide gaps need tape
behind them when edge-gluing the chines. Took some extra care with shaping this
time - no wide gaps. YOU BEAUTY !!! :2tsup:

Tied frame 1 on temporarily to assist shaping at the bow. There's a fair bit of twist
needs applying to the tips of chine 4 to bring the ends fully vertical.

Pressed down on the narrow strip behind the cockpit until it's just slightly raised in a
sweet curve. Mark the overlap on each side & remove half of it. Tie it & weight it in
place - a soft drink bottle can easily have its weight adjusted to suit the ply stiffness.
Tie the two triangles back in - they don't fit perfectly. If clear finishing the exterior,
there'd need to be a fair bit of twisting & bracing these to sit nicely along their edges.
I use paint so can hide the unfairness with filler. This whole fancy cockpit back is
pretty optional, but I like a lowered back on a smaller cockpit - much easier to get in &
out of it.

Epoxy has pot life of about 30 seconds in this heat, so only mixing very small batches.
The scoops out of Omo front-loader powder are ideal for these. Handle to keep fingers
clean, & cured 'pox pops out of them easily - many re-uses each.

I use a 25cc syringe to feed epoxy into the gaps. Neat epoxy first to wet the ply, then
as thick a brew of filled 'pox as the syringe can pump to fill the gaps. Usually this is a
two or even 3 day process, but with it so hot, gaps filled & curing in 1 evening (still 36C
(97F) at 21:00).

28/1/09
Cured by this morning. Pulled all the ties, & levelled all the lumps & bumps with the
dreadnaught file. Sanded everything smooth & rounded chine edges, ready for glass.
Will need to put a little extra filler in a few spots... pretty normal. About a 20 minute
job. Pretty exciting at this point can already see the shape & style of the boat.

The 3D structure is already strong enough to take off the strongback & handle around.
As there is no rush to tape joins or glass the outer, I will probably do the coaming
next. Once the upright part of that is in place, it will be even more rigid.

The other thing I realised whilst sanding - the outer tape on the butt joins can probably
be sanded almost completely away once I'm ready to sheath it. This will allow the joint
to totally disappear. Sad that it's taken 5 boats in this syle of build to realise this...

Been picking away at it in between other commitments.
Thought I'd made little progress until I looked at this log.
Missed a few steps of taking photos too.

4th Feb 09
cut & fit coaming riser.
I use 5mm bendy ply. Amazing stuff. Bought a sheet 5 years ago, roledit up & brought
it home on the back seat of the car. Wish all ply was that easy to transport !
Cut a couple of notches in bulkhead 2 to support it at the right level. Cut a 120mm
wide strip of bendy ply, wrap it around inside the hole, mark and trim excess length.
Dry fit with packing to get good fit all round, and tack in place with neat epoxy squirted
into the joint with the syringe.

the tack gluing is not strong - most soaks into the timber.
It will need a large fillet to make it strong enough to support a heavy huming bean
entering & exiting, but will do that later when I glass the outer deck. For now, a small
fillet is all that is required to make it strong enogh to work around.

The deck comes off the molds then, and the gaps in the tacking are filled.

11/2/09
Trimming the excess off the underside - free-hand with a jigsaw.

At this point I took a step or two backwards... Incautious handling of the deck (I dropped it) caused a couple of the glued edges to crack. So I had to bring forward the taping of the seams. Was going to leave this until nearly ready to join deck & hull to
avoid changes in humidity changing the shape of the deck & hull (as discussed in a thread a year or so ago.) Not all bad though. Took advantage of it to adjust the shape at the stern to better fit frame 8, which will be the rear wall of the gear stowage compartment (the first I've ever done)

once cured, tossed the deck under the workbench & started on the hull